


Blueberry Surprise

by BadDecisionsAndGoodWriting



Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Awkward Sexual Situations, Bondage, Ecto-Genitalia (Undertale), Ecto-Penis (Undertale), Ecto-Tentacles (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), F/M, First Time, Loss of Virginity, Love Confessions, M/M, Magic, Mating Cycles/In Heat, Reader-Insert, Teasing, Tentacle Dick, Underswap Papyrus, Underswap Sans, gender neutral reader, undefined genitals
Language: English
Status: Completed
Published: 2017-12-16
Updated: 2017-12-16
Packaged: 2019-02-15 17:55:33
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 10,498
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13036383
Author URL: https://archiveofourown.org/users/BadDecisionsAndGoodWriting/pseuds/BadDecisionsAndGoodWriting
Summary: You’re going through a bit of a… the internet seems to be calling your current predicament “heat”, but you just call it “those weird times where I get super horny and need to pump a couple out so I can rejoin society as a hardworking, totally-not-perverted citizen”. Lucky, lucky you gets one of these when you’re over at Sans’ house. An even luckier you gets found out by the little guy as you’re trying to alleviate it. You aren’t surprised that he found out about your weird “thing” (he had to find out some time, you think), but his reaction is… well, he’s nothing if not eager.





	Blueberry Surprise

**Author's Note:**

> For updates on stories, sneak peaks, and occasionally fanart please check me out at [TheHeraldOfTheDark](https://theheraldofthedark.tumblr.com/).
> 
> Anyways, I hope you enjoy the story.

It’s about the fifth musical number, if you’re counting right, in the musical you’re watching with Sans. The actors are jumping, spinning, dancing, and generally making you feel like you need to exercise more. No matter what they sing about, their enthusiasm pales in comparison to the merry skeleton on the slightly grody couch next to you. Of course, he picked the movie, so his boundless enthusiasm is anything but surprising. He invited you over to hang out, but he also insisted that you both watch the classic musical he had stored in his room. He nods his sweet little head along to the cheerful beat, taps his toes (though they don’t reach the ground), and hums along to the songs he surely has memorized.

Then there’s you: sweating, aching, breathing choppily, rubbing your thighs together for some much-needed friction, and trying to make it not obvious that you’re frustratingly turned on. You wouldn’t say you’re in heat, that’s for uncivilized animals, but you would say that if you happened to spot a dildo or a fleshlight or even a dumb body pillow you’d have pounced on it already. You’re not sure why these damn things happen: the scientific part of yourself suspects it’s a genetic thing or maybe even evidence of a sex hormone gone haywire, the more superstitious part of you insists it’s some punishment by any number of gods or prankster spirits having a good laugh. If nothing else, those thoughts offer a momentary distraction from the burning in your nether regions.

Usually, you can predict when these things happen, saving the people around you from having to deal with you trying to jump them or something worse. This time, though, it just sort of crept up on you. You don’t know if you lost track of the date or if those spirits really are cursing you, but ignoring the first few you had, this has to be the worst timing ever. It just had to start up around the monster you just so happen to have a crush on, didn’t it? The guy you consider your best friend (or at least a very good one), work-out partner (you normally just tag along), and potential love interest just had to be in the room when it started. Sure, he might have been on your mind the last few times it happened, and sure you’ve dreamed about this happening in your less controlled moments, but you aren’t about to ruin a great relationship with your own uncontrollable libido.

If you had your mind in full working order, you might have considered whether your body was trying to get you two together, but if you dare follow that road you might just start humping the poor dude. You dare not look at Sans for more than 30 seconds at a time, in the fear that if you see his cute little face you just might _sit_ on it. Oh, he’d be so confused, wouldn’t he? You mean, he’s probably a virgin, so he would have no idea what you wanted. But his own libido would take over, and he’d just know that he needed to start licking. As he tongue fucked you, he’d start getting hard, and just when he’d had enough you’d reward him by letting him thrust into you. You’d be in the lead, of course, and the sounds he would make would echo in your mind every time you saw him. When you both would be about to finish, you’d lean down and kiss him for all he was worth.

“This is the best part,” Sans gestures to the TV screen, “it’s where the leads realize how much they—hey, what’s wrong?” You don’t glance over, but you can feel the concern in his voice and make out a worried expression in your peripherals.

“Nothing,” you say, keeping your eyes glued on the screen, “I’m just peachy.” Welp, that marks the second time you’ve had a completely inappropriate intrusive thought about him today. Congrats, libido. Thank you so much for making this way harder than it has to be.

“Are you sure?” he says, leaning a bit closer, “you look really red.” He gasps, “oh stars! You’re about to cry! I’m so sorry, I forgot how much more emotional fortitude the magnificent Sans has than other people.”

You sigh in amusement, “No, I’m not crying Sans.” _Emotional fortitude?_ you ponder, _yesterday you cried because you put the wrong kind of cheese in your taco._

“Oh, I see.” He turns back to the TV for all of 5 seconds before he screams again, “you’re sick! That’s why you’ve been writhing!”

Your heart catches in your throat as you realize he’s been paying attention to you, “What?”

You jolt as his ungloved hand touches your forehead, “Oh geez! You’re burning up!” Your composure is tested as he drags his hand across more of your fiery body, “Mweh! Your whole body is burning up! No wonder you look so uncomfortable!”

You swat his hand away, accomplishing little more than exacerbating his worry, “I’m not sick, Sans, and please don’t touch me.”

“Then why are you so red? And so hot?” He doesn’t give you a chance to sputter out an answer before he “realizes” what’s going on, “Oh I get it! You must be embarrassed to be so weak in front of the magnificent Sans!” You can just see his proud pose, “no need to worry, though I may be a tough royal guard, I would never deny my friends the care they deserve.”

You take in a cleansing (if you ignore the heavy musk you’re giving off) breath of air and force yourself to take the easy out he’s giving you, “You’re absolutely right, Sans, I was sooooo afraid that the most important of the royal guard would not be able to understand my struggles.” You admit, you’re laying it on thick, but it _is_ Sans: it’s pretty much the only way to compliment him.

His chest puffs up like a cute peacock, “Mweh heh heh, I knew that my reputation would intimidate you, it’s only natural. Do you need medicine? I think it’s somewhere in the cabinet.” Sans stands up off the couch, coming dangerously close to entering your line of sight.

“No, no! You don’t need to stand up!” you insist, blocking him out of your vision with your hand, “I’ll just… go home! I don’t want you to get infected.”

Sans scoffs, “don’t be so ridiculous, skeletons don’t get sick! And besides, what kind of monster would I be if I allowed a sick friend to walk alone in this weather? You’re going to lay in my bed until Papyrus gets home, so he can teleport you to yours!”

You consider the possibility of just leaving on your own, but a sudden pang of need convinces you otherwise. “Sure,” you wheeze, “laying down does help a little bit.”

“That’s the spirit!” Sans proclaims as he grabs you by the arm, “and, after all, what kind of host would I be if I let my guest writhe on that dirty old couch? My bed is much better!”

You suppose Sans has always been a perfectionist: in everything from relationships to cooking, he won’t rest until everything is perfect. Apparently, this includes being a good host. What a sweet guy he is—oh good lord he’s taking yOU TO HIS BED AAAAAAHHHHHH THIS WASN’T PART OF THE PLAN. The lustful thoughts seem to get more excited when he leads you up the stairs and his adorkable butt is right in your face and _what the hell did you do wrong in your past life to deserve this Oh God_. It’s only his strong grip that keeps you from ripping off his “battle body” right here and now.

“Well, [Y/N],” he says as he unlocks the door you weren’t aware you had arrived at, “feel free to make the place your own. Undyne has told me how awful getting sick can be, so I understand if you need to cuddle up with one of my stuffed animals.”

“Wow thanks Sans,” you say quickly, ripping yourself out of his grip and swerving your way into his room, “it’s so kind of you to offer me a place to stay because I know that you guys don’t have a guest bedroom even though that’s a common feature of houses but I guess you could have bought it as a house meant for a couple or a single person to only have one bed and—.”

“Uh, do you want me to stay with you? I don’t want you to get bored,” he says as he tries to keep up with your speech.

“What? Pft no that’s ridiculous why would I need that I can entertain myself I was going to any way I mean even though you haven’t gotten sick doesn’t mean you won’t and not even I would want to hang out with a sick person there just so annoying and unfun and maybe you should keep watching that musical I know it’s your favorite go have fun ok bye.” You slam the door before he can either question the words coming out of your mouth or worm his way inside.

You can hear him tell you something about getting better and being sick before his foot falls trail down the hallway and back to the living room. You slump against the old, wooden door, taking in large gulps of air to calm your racing heart. That was close, that was absurdly close, that was so close that you’re pretty sure the very atoms of the event happening and you losing control touched. Your hand is already down your pants, the button and zipper mysteriously already undone. His confused, innocent face is all you can see as you senselessly rub the climax that had been begging to be released out. It’s not even very satisfying, the high lasts for a second before flattening out into an ever-increasing need.

You stumble past the box of bones and flop onto his adorable star-hammock observatory bed. You can’t even force yourself to get under the covers before you’re peeling your sweaty shirt off to get to your chest better. You throw the garment carelessly at Sans’s collection of alien paraphilia, knocking the closest one to the floor. You briefly consider using his computer to look up something dirty, but A) he would definitely find out and B) you already have all the material you need. True to his word, his bed is surrounded by adorable plushies of all kinds of nonsense. You grab the closest one, you think it’s a cat thing, and start humping it with your newly exposed privates.

The higher part of your brain is cursing you out for being so dirty in your dear friends own home, for getting so worked up over the mere presence of your crush. It mocks you for being so desperate that you would resort to rubbing yourself out against his own toys, something you know he never intended you to do. It scolds you for abusing his generosity, for not putting your foot down and leaving like a normal person. It degrades you for lusting after someone so innocent, so pure compared to you—for wanting to take that innocence before he even knows how you feel about him. The shame, though powerful as it is, does nothing to slow your fervid thrusts; if anything (and you truly do hate yourself for this), it only serves to inflame your need.

The lower part of your brain is begging for you to keep going, to satisfy the endless urge. It gifts you with images of Sans’s adorable face twisted in need, his face flushed aquamarine and his soul pulsing with lust. It lets you imagine that the cat-like plushie really is him, despite the obvious size difference. It goads you on with fantasies of Sans, all the things you ever dreamed of doing to him only made more intense by the fact that you’re in his own home—the fact that he’s just below you in his living room is driving you mad. The lust, as it already floods your entire system, forces your body to move in spite of your disgust; though you have to admit (and you’re slightly grateful for this), you are still polite enough to not be getting off as much.

The plushie is a complicated little thing, barely any place where you can really get a good thing going. The fabric is too smooth to get much friction going, too. Worst of all, it’s so cute and innocent you feel like you’re some kind of mega-level sinner. The only thing that keeps you from choosing something else is that it has such a varied shape that it accidently stimulates your sensitive areas. That, and it kind of smells like Sans which is really doing it for you. Wait, that’s 2 things. Oops.

Your mind drifts away to how much the skeleton brothers would be flipping their shit if they saw you like this. You’d probably never get invited back. This has to be the biggest sin a houseguest could commit. Not even the ancient Greeks would be able to suffer this, and they were freaking crazy about respecting house guests. Like, Papyrus would have your head if he saw this. Especially because you’re doing it in his brother’s room, with his stuffed animals, without anyone’s permission. By God, Papyrus gets antsy if you stay out with Sans for too long! You don’t even want to imagine what Sans would say. You can practically see the horror on his face right now, made worse by the lack of full understanding.

“Wowzers!” the world stops spinning for a moment as you hear his adorable voice from the door, “I _was_ right after all!”

You cringe as another climax floods your system, hopefully only because of the surprise. “I’m so— _hnng_ —sorry,” you pull his neat blankets up to cover your exposed body and to block him from your sight, “please don’t— _oh God_ —hate me.”

“Mweh? What are you talking about, [Y/N]?” he steps closer to your impromptu blanket shield, “why would the magnificent Sans ever hate his friend for being sick?”

“Because I’m disgusting—did you say sick?”

He giggles, “why of course, silly! The internet told me that your kind gets these “heat” things that get you really excited. You know I would never abandon someone who needed my help. Besides, I kind of knew about them already.”

“You knew?!”

“Well, I didn’t know what they were until now. I thought it was really weird how you kept cancelling our hangouts so randomly, and how it would always be because you were sick. Plus, I could tell you were really horny while we were watching the movie! With my excellent sleuthing skills, it was only a matter of time!”

Oh, that’s just wonderful, he knew something was up the whole time, why didn’t you just tell him? Maybe you wouldn’t be in this situation right now. “That’s _great_ —great, Sans, but uh… it’d be better to just _fu_ —leave me to it. I can handle this just fineeee.”

“What nonsense!” your heart double-times when you feel a sudden pressure on the bed, “what kind of friend would I be if I left you with just my Temmie plushie to keep you company! Obviously, I’m going to help you through this! The internet had all sorts of tips.”

“All… sorts… of… tips…?” your body practically vibrates with the effort of holding yourself back.

“Mweh heh heh,” he chuckles in an attempt to be seductive, “don’t worry, [Y/N]. Although the magnificent Sans may have not done this before, there is no task that I cannot master.”

“Sans,” you say with the very last of your self-control, “I don’t think I’ll be able to stop myself once I start. Are you really sure you want to do this?”

He scoffs in that innocent way that tells you that he only found out about this a few minutes ago, “are you doubting the magnificent Sans’ abilities? I’ve always been happy to help you with any problem you’ve had, this is no different.”

Before you could even say “what in Hell’s name is a Temmie?” you toss the blankets aside, grab the overconfident Sans, pin him to the bed, and just go to town on him. It’s odd not having any lips to kiss, but his mouth moves to meet yours anyways in a clumsy display of his lack of experience. His kisses are quick, yet he fails to truly catch up to you in both speed and skill. It’s the honesty of it, the inexperience, but also the determination to reciprocate that has you whimpering into his boney mouth.

You aren’t a mind reader, but even in your fuzzy state you can tell that he’s not entirely sure what to do. Sure, he is kissing back—and with a hell of a lot of passion to boot—but the rest of him is nearly motionless: his hands don’t go anywhere except his sides, his legs are firmly clasped together, and even his eyes are shut tight as if he’s concentrating. Deciding that this just won’t do, you break from the kissing momentarily to help him. You position his arms around your neck, his legs around your middle, and luckily his eyes are wide open as you do this so you don’t have to worry about them. As you look into the white dots he calls eyes, a bittersweet feeling fills you. This is exactly the position you’ve dreamed about being with him in for so long, but the fact he’s only doing it to satisfy you—purely as a friend no less—is an awful, sickening feeling.

You restart the kissing session by licking his teeth (a weird feeling through and through) to really get the party going. He just kind of looks at you like you’ve sprouted a horn in the middle of your forehead, clearly not knowing what that could possibly mean. Not wanting to deal with an explanation, you settle for using your new position to thrust your crotch into his pelvis. He gasps, so cute and innocent-like, and you take the opportunity to do the most classic move in all of porndom—you french him. His mouth is, predictably, cold and completely lacking in flesh. You can’t bring yourself to care, though, so you drink up the feeling of his perfect mouth on your tongue.

Somewhere in the haze of drinking him in, you notice that he’s still not really doing anything. He has taken to hugging you tightly along the neck and hips where you placed his limbs like you’re his only line to the real world. Other than that, he’s still so still you curse yourself for your endless libido. You had suspected that he never did it with anyone, partly because he’s just so innocent all the time but mostly because the skeleton still collects plushies like it’s a religion. You wish you could slow down and just take your time with him, you wish your libido was normal and that you would’ve just spent it at home today, and you wish you weren’t making yourself so sick that you can barely enjoy this.

It’s when you trail your hand down to his crotch to tease him through his… _what is that, a jockstrap for his entire pelvis?_ pants that he finally reacts. Your whole body feels impossibly heavy, like you suddenly agreed to take the sky from Atlas or maybe just 90 pounds you don’t know you’re not that strong. Sans doesn’t seem to react to your sudden weight gain, and neither do the bed sheets. All at once, something pulls you up so that you’re pulling an exorcist or maybe a ghost buster, your naughty bits dangling in the air like some kind of embarrassing ceiling decoration. The sight of your blue, glowing bits finally clues into your brain that Sans is using his attack on you, which also explains why you’re otherwise inexplicably floating. Your body flips over without any input from you and you plummet back to the bed like a sack of dildos.

Luckily for the both of you, you don’t land on a pile of bones and plastic costume armor, you just land on the slightly less hard surface of his bed. The poor thing responds with a creak that tells you Sans jumped on this bed so often the springs probably can’t take a feather falling on it, and you’re much heavier than a feather. Your non-feathery muscles have just enough leeway to glance over at the skeleton technically holding you down. Sans’ face is screwed up in adorable concentration, yet there’s also something like embarrassment and a bit of a fluster to him. Aquamarine tints his pudgy (can skeletons be pudgy?) cheeks: probably a mix of embarrassment, fluster, and hopefully arousal. The possibility that he restrained you because you were doing something bad to him crawls down your back.

“Sans?” you croak, “I’m sorry.”

“You should be,” he squeaks, the odd look not leaving his face.

Despite how far gone you are at this point, tears still manage to fill your eyes, “I’m so sorry, I’m so sorry, I… just lose control sometimes.” You flinch, fuck, you sound _exactly_ like some kind of rapist, “I know that isn’t an excuse, but—.” You’re stunned into silence as Sans crawls back onto the bed and onto you, finding his perch so his bottom is on your calves.

“You can _bet_ it’s no excuse, [Y/N], how can I help you if you don’t let me?” his face, though still flushed, is nearly back to its usual beaming smile.

You can’t seem to find the sense to answer him with, “What?”

He giggles one of his heart melting giggles, “silly, how can I try out any of my tips if you’re the one taking the lead.”

“Oh, right,” you curse yourself for the tears that still run down your cheeks, “sorry, I must have forgotten.”

“Being sick will do that—hey, why are you crying?”

 _It took him this long to notice?_ “Oh God, I’m sorry Sans, I don’t mean to be.”

“And why do you keep saying sorry?” One of his hands goes to stroke your exposed skin, “I know my skills are truly something to look forward too, but I wouldn’t hold it against you.”

“I thought,” your voice cracks, “I thought I was assaulting you.”

Sans pauses in his sweet petting, then gasps and throws himself onto you, “Oh no no no [Y/N]! That wasn’t it at all! I just… got a little overwhelmed, that’s all!”

“Is that why you tossed me around like a ragdoll?” you ask him, wanting but unable to hug him back.

“Mweh heh heh, our coupling was so intense, my expert fighting response skills were called into action, and a royal guard such as me cannot afford to let my reflexes go to good use. I had no other option but to subdue you!” He chuckles sheepishly, “plus, I didn’t know what to do when you grabbed my… you know, so I kind of panicked a little.”

You give a wheezing laugh at his ridiculousness, “and why you’re still doing it?”

“Umm,” he blushes harder, raising one hand up to cover it, “you did say you had a hard time controlling yourself, and I really want to try out my techniques on you.”

You let out a knowing “ohh” sound, “I see what’s going on.”

“What?” Sans asks cautiously, catching through all of his innocence that something was up.

“You’re into bondage!” you proclaim naughtily.

“What?!” He bursts into color, “I don’t—what?!” He squirms against you, his soft petting completely abandoned now.

“Oh, come on,” you say, “holding the unruly captive down, just so you can do whatever you please to them? That’s _textbook_ , dude.”

“That’s—that’s not what I was doing! And you’re not my captive! That’s weird!” Both his hands shoot to his face, and his head bows in adorable shame.

“That’s not what Chara told me about you. They told me you were suuuper eager to have a captive human.” Should you be teasing the guy you like for liking something that you also like? Probably not, but you’re not going to stop anytime soon.

“That was for the royal guard!” he shrieks, “it was completely different!”

“Oh I’m sure.” You may not actually have any proof of this, but it seems like a good guess, “is that why you have it all over your computer? Don’t think I don’t know about that.”

He screams in frustration and slaps his face onto yours for a kiss. You joyously match his far faster pace (though anything is faster than not moving at all). He still clearly doesn’t quite know how this type of thing works, and not having any lips is not helping him, but he’s so feverish you can’t care. There’s a passion in the awkward sliding of his teeth over your lips, of the choppy movements of his bones that sends your heart a-flutter. You really did not expect this kind of thing from him, both the kisses and the bondage thing. You’re in for one hell of a time.

You break from the passionate meeting, “And you shut me up with a kiss? C’mon, that is sooo bondage that I don’t even want to think about it.”

His body shakes until he spews out the truth like a sexually frustrated volcano, “please don’t tell Pappy! He doesn’t know I look at that stuff!”

“Your secret is safe with me, Bluebs.” In a different circumstance, you might have talked with him about open and honest communication with his brother. Right now, though, the only thing you can really think about is satisfying the urges in your loins.

There’s a strange lull in activity where the both of you don’t say or do pretty much anything. Your excuse is that you’re waiting for Sans to do something. That, and the fact that his magic seems to have gotten stronger as you can barely lift a finger. He might excuse himself by saying that he’s simply remembering all the things he needs to do. That, and the fact that he’s never done anything like this before. The only thing Sans does seem to do is look over your desperate form like you’re a recipe he’s never done before. The only thing you can do is move your head around, and your lips and eyes and other face bits.

“Stop staring and show me those tips!” you demand, using the one part of your body his magic seems to have left mobile.

“Ok you don’t have to shout at me!” he shouts, squirming even harder.

“Sorry, but I’m kind of swimming in every hormone imaginable and I’m a little grumpy about it!” Grumpy, impossibly horny, same thing. “Can’t we just skip to the part where you fuck me?”

“Of course not! None of my guides said anything about skipping to that part first!” He pulls out his phone as if to prove it to himself, “all of them say that going too fast would only make you want more! They say that in order to get rid of this ‘heat’ you need to go slow!”

You think you can feel a part of you die, “I don’t think I can take slow, Sans.”

“It’s going to go even slower if you keep interrupting me!” he chides, clearly missing the light dying in your eyes. “Now it says the first step is to… oh!” He suddenly shoots off of you and stands up on his bed. “It recommends that I slowly take my armor off! What strange things you need to do to help the sick.”

You watch in stunned amazement as he flops down onto the bed to shuck his boots off onto the floor. They each come off with a little “pop”, revealing his thin and yet somehow chubby skeletal feet. The next to go are his blue gloves, each one taken off tantalizingly slowly. Your mind swims with all the things those hands could do to you, random guides on the internet notwithstanding. Instead of taking off his scarf (or is it a cape), he delicately drags his shirt past it and over his head. It gives you a momentary glance of his soul before it gets covered up again by his scarf. Finally, and you’re really sweating at this step, he nervously drags his pants down to reveal… a pelvis. Just a pelvic bone. There’s not even any hint of any sexual parts.

The fire building in your loins due to the sudden strip-tease suddenly shifts into a shameful heatwave as you realize that he doesn’t have anything down there. Does he even have anything to have sex with? Did he mislead you? Did you mislead him? Why did you even come in today? Fuck, you should just tell him that you would like to go. At least that would save the both of you this train wreck of an evening.

“Hmm, something is wrong,” Sans mutters, “that doesn’t look like the picture.” You look up from your shameful moping to see him glaring at his smart phone. “Hold on a minute, [Y/N], there’s something I need to find out.

“I don’t know why I expected you to even have anything down there,” you say, knowing that if you had your full wit you would have never said that like that, “you’re a skeleton for Christ sake, that’s not how this works.”

A surge of aquamarine in his chest interrupts you. You can’t help but notice how similar it is to the glow around you. The color trails down his spine, presumably the thing that causes a shiver down his body, and drips into his pelvis. More and more of the color begins to pool down at his crotch, coming together to form a bright blue mass. Looking at it is strangely difficult as it seems to constantly shift and form into different indescribable shapes. It is, however, placed where you’d hope someone’s junk would be. You can’t really tell if he’s trying to form lady bits or manly bits, but at this point you could go for either. Looking into his flustered, frustrated face you doubt he knows what he’s going for either.

“You, uh, having some trouble there, Bluebs?” you ask, far too ready to just mash uglies already to be a caring friend.

“There don’t seem to be any useful guides on how to form… those things from magic.”

“Is that why there’s that weird thing on your hips?”

He seems surprised to see anything on his crotch at all, “Wowzers! I really did it!” Sans looks to you excitedly, “I think I can follow the rest of my tips with this. What do you think?”

“You could fuck me with a rusted pole and I wouldn’t complain right now.”

“Mweh heh heh, that’s bad for your health! I’m sure that the magnificent Sans will be plenty able to cure your illness!” He presents the strange glowing mass to you, “the guide said that the best way to cure this condition was to either inject the sick person with creation fluid, or to let them inject it into you! I believe that this… whatever it is could do either. But which one would you prefer?”

You look at him blankly, assumptions about what you needed that seemed clear to you apparently as unreachable as the top shelf to your friend. You turn your attention back to the thing on his hips, wondering how it could do either of those things. Your mind, the dirty thing, doesn’t seem to be able to care about what it is. It only demands that you use it one way or another. You can almost see the beginnings of both, part of it seems to be slightly elongated and the other hugs him. They’re both still very chubby, something that you can definitely appreciate. You’re not sure how it works, but the aqua colors seem to condense around the sides of the strange mass no matter how you look at it. This odd property gives it an interesting blueish clear center, giving you a better look at it. That being said, you still have no clue how it would work.

Before you’re aware of the thought even existing, your hand suddenly shoots out to touch it. Sans keens at the sudden attention, body freezing into a flushing statue. You playfully stroke it, guiding the magic along your fingertips like a conductor to a band. It desperately clings to your hand, the odd material squeezing and tugging back at you. If Sans truly didn’t know what he was doing, you’d have to guess that it’s his body—maybe even his magic—that’s reacting to you. Sans, of course, also reacts to your sudden jerk off. He grabs your hands and whines about how this wasn’t part of the plan. The mass doesn’t seem to know how to form anything close to any junk you’ve ever seen, even as you try to guide it into a recognizable shape, but the firmness of it gives you some hope for a proper fuck.

Your limbs feel heavier, no doubt from his magic, yet the weight he seems to put on you falters as you stroke. There’s really no blame you can assign to him, if someone was giving you a hand job, you probably wouldn’t be able to focus on anything either. You’d do so far as to speculate that it was the conjuring of whatever the hell you’re holding that even allowed you to move in the first place. Normally, you might not have minded being held down: you’d like to think that you’re very open to things like this. Yet, in your mind clouding state, you don’t think you really have the determination to not move.

Distantly, you recall that he wanted to know what your preference is. “You,” you swiftly correct yourself, “are fine. This is fine.”

His answer to your answer is a shuttering gasp, “you’re perfect.”

Your limbs turn to stone as the kind of thing you’ve dreamed about him saying flutters out of his mouth. “Excuse me?” you whimper hopefully. Your hands fall back down to the bed out of shock and the sudden burst in magic.

“The tips said,” he taps at his phone, “compliments should help you along.” Before a sigh of disappointment can creep out of your lips, Sans blurts out a small confession, “plus you made me feel so good. Better than I ever could. Also, the look you had on your face made me feel all weird, but in a good way? How did you do that?”

You manage to cover your eyes with your arm, “I don’t know Sans, can we _please_ move along now?” You don’t think you could go another second with this whole teasing thing. Or the whole “I love you but I can’t tell you that” thing that you’re going through. Please, please let the next tip be a good one.

“‘Once your partner is ready,’” he reads, “‘begin by touching their erogenous zones’.” A puzzled look zips across his face, “I thought we already started. Oh well.” Cheerfully, he turns to you, “are you ready?”

You look at him with your body glistening in sweat, and the unmistakable smell of sex wafting out of every part of you, “if you don’t do something in the next five seconds I’m going to— _hnnggg_.”

He smiles innocently up at you as he fondles your chest, “what’s a hnnggg?” He moved, you blame the moment for your lack of perception, so that way he was kneeling over your chest. His knees are on either side of your abdomen, his weird candy blue bulge hovering right over your stomach.

You, in all your wit, can’t find the words to answer him with. All you seem to be able to do is moan while he pulls and prods at your nipples indiscriminately. The odd coldness and hardness of his bones is completely foreign to your fleshy chest, forcing your nipples to harden against his strokes and pinches and pulls. Calming and yet arousing waves pulse out from your chest at his gentle exploration. A strange sensation of being cared for, yet also of lust fills you as his boney fingers rub them. Save for the warmish mass you can feel hovering over your belly, courtesy of his lack of knowledge about anatomy, this is exactly how you imagined being with him would feel: calm, caring, and unfathomably perverse (the last one on your part).

One of his hands abandons your chest (with a selfish little whine from you) to once again consult the ever-present guide that is the internet. He lets out an adorable little “oh” at whatever it is that he reads. In that moment, you can see the candy blue tongue that you usually only see when he eats. Two guesses as to where your mind goes. He leans over you, finding he needs to scotch down your body to get in a more favorable position. In doing so, he drags his unique genitalia closer to your own, much to your pleasure. His hand that was playing with your hard-as-steel nipples falls away in favor of steadying himself. His mouth is right over your neck, not much warmth comes from his fleshless body, but the magic in his tongue gives you plenty of clues as to what’ll happen next.

His tongue, a far more accurate representation of the real anatomy, pops out of his giant grin and onto your hot neck. Sparks of magic and his own excitement burrow into your skin, sending a pulse of him to every nerve they hit. You suspect that the amazing feeling from his magic is mostly due to the heat in your loins, as no other magic item made you feel quite like this before. As it glides over your skin, it’s peculiar makeup sends shockwaves of some foreign form of pleasure you’ve never felt to every end of your body, effectively paralyzing you in bliss. There’s a kind of wordless awe in his licks, each one slow and languid like he’s worshipping your very flesh. His head is forcing yours to tilt to his will, yet one of his hands keeps it in place so you can’t squirm away from him. Not like you ever would, of course. Maybe it’s the heat, but you can’t help the meaningless praises that tumble from your lips—you think you complimented his singing ability a few seconds ago.

You doubt he understands what it means when you suddenly cry out as he passes over a particularly sensitive part of your neck. The way your hands suddenly pin him to that spot, however, you think gets through to him. He begins to press a little harder into that one desperate spot, and you accidently reward him with the most overdramatic moan that’s ever managed to leak out of your mouth. He even, though you’d guess it was on accident, grazes over it with his teeth.

Without a warning or meaning, you thrust your hips upward so they knock into his warm bulge. Without a warning or meaning on his part, the aqua mass sort of sticks to your crotch even as you jerk it down in surprise. His mouth breaks from its place on your throat to all but scream in a mix of white hot pleasure and unintelligible confusion. You let out a series of no less confused and yet intensely lustful noises at the sudden shot of his painfully pleasurable magic to your most sensitive part. You howl when his obviously out of control magic worms its way inside you, the usually sensitive flesh there only made more so due to your heated state. Before he can regain his composure and figure out how to untangle the two of you, he can’t help but grind into you.

It’s only when he raises his head to look you in the eye, and you catch a glimpse of his starry, desperate eyes that you find your body spasming into your end. Cum pulses out of you, or as Sans called it your “creation juice”, soaking his bluish bits in the fruits of his labor. Your insides clench down on him, trying to milk him for the cum he isn’t quite ready to give you. You drag his face down to yours, all but devouring his confused mouth with a need to have every part of him in any way you could. One of your hands, in your frantic spasms, makes its way into his chest and brushes past soul. The burst of overwhelming intensity pushes the already overstimulated skeleton to dart away from you, effectively ending your end.

You lie there, panting, sweating up a storm, and trying to find something that resembled words to answer Sans’s perplexed expression. The heat, the damnable thing, would barely allow it. It only gives you a second of relief before it sparks up again. Those few seconds are sweet as can be, though. The momentary afterglow fills you with a sense of joy at finally having done it with your crush, even if it was slightly one sided. The moment the sweet feeling leaves, you’re left with an urge even stronger than the last: one that knows that a suitable mate is so close to you, and so willing to solve your problem.

“I don’t think that was how my guide said this should go,” your “mate” pipes up, voice a mix of surprise, frustration, and arousal.

“Sorry,” you lie, “I didn’t mean to.” You’re not sure if he catches the gluttonous need in your voice, but it stands out to you as clear as his magical ding-a-ling. You don’t think you’ll be able to keep your composure for very long this time.

“It takes a lot of determination to overcome my blue attack,” Sans says, for once doing some critical thinking, “so you most definitely meant to do that!” You perk your head up enough to catch a glimpse of his sort-of frown. “Can’t you just wait long enough for me to do what I need to do? I mean, really [Y/N]? I was about to get to that! You skipped ahead several steps in my tips!”

Maybe it’s the lack of relief, maybe it’s the sassy tone of this impudent monster, but you snap at him in any case. “Do you even fucking understand how painful this is?” you shout at him, finding the will to sit up in bed. “Cause let me tell you,” you laugh bitterly, “it’s pretty fucking bad.” You begin to ramble, “this is absolute torture, the worst a person could go through! No matter what I do or how I do it, I never seem to get better. And here you are, Sans, trying to ‘help’ me by edging me like it’s some kind of joke. I thought I loved you, but if this is the kind of shit you’re willing… to… oh…” You pause in your rant to take a mortified look at his sweet, chubby face as he covers it in tears. You jump forward to try and reconcile what you’ve done, “Bluebs! I’m so sorry! I—I didn’t mean to—.”

He raises one skeletal hand up, silencing you. You lean on your heels, waiting terrified for the inevitable heartbreak you were about to go through. “[Y/N],” he starts, the cracking in his voice sending tears to your face, “I… can’t believe you said that.”

“Sans,” you squeak, “please try to understand.”

“I,” he lets out a momentary sob, “I understand very well.” He puffs up his chest, slightly less effective when you don’t have a set of lungs, “I just… can’t believe you said it first.”

“Sans, I really am… excuse me?”

“I’ve been waiting for some kind of sign that you had fallen under the magnificent Sans’s charms for so long, but this?” He sniffles again, “is far beyond what I had expected. Your insults were just as Undyne told me they’d be! I know it must be difficult to harbor an affection towards someone as amazing and magnificent as me, so I expected it to come out in such a self-deprecating way. But the level of pain you’re going through right now, just for me,” he sobs, “it’s just so moving!”

“Huh?” You think he’s confessing something to you, but you’re not that sure actually.

“No need to deny it, [Y/N],” he waves his hands at you, “your shame is shared. I too was afraid of telling you how I really felt, so much that it hurt some days to call you my friend.” He wipes a tear from his eye socket, “that’s at an end now. Finally, [Y/N], I can admit to you that I always thought I loved you too!”

Despite the inherent goofiness and the clear lack of actual understanding, you find tears flooding your eyes. “Sans, that’s so sweet.”

He continues, almost unaware of your admission, “The magnificent Sans is sorry for putting you through such torture, the time we spent together must have been so painful for you.” He looks to you again, hope and sincerity shining through his eyes, “from this day forward, I will make certain that every moment we spend together will be perfect!” You can’t help but pull him into a deep embrace, his blue attack dissipates as he joyfully hugs you back. “Can I guess,” he comments into your chest, “that this ‘heat’ of yours is satiated now? I mean, we both said our parts, you can drop the act now.”

You pull back roughly, “Sans, I’m really in ‘heat’.” You ignore the slight hurt that comes from him assuming you were lying.

“Oh,” he says, blushing.

“In fact, I kinda want to pound you more now.”

“Oh,” he says, flushing.

“In fact,” you grin nearly maliciously, “I think I’ll start right now!” You push him to the bed underneath you, the ceiling light casting you in a heart pounding glow despite the shade of his canopy.

“Oh!” he squeals as you bump your already reheated privates into his. “This isn’t—this isn’t what the guide said.”

“Screw the guide,” you growl, “I’m gonna screw ya.”

“Oh, Stars!” he breathes as one of your hands sneaks back under his ribcage to tease his soul. You don’t have any intention of actually teasing him, you would just rather play delicately with the thing that literally keeps the guy alive. You can’t help but momentarily marvel at the life you feel coursing through your hand as you skim across his soul. You’ve never felt this connected with anyone before. You only hope that you can do it more in the future.

“That’s right,” you rumble, “moan for me, Sans.”

Your heart does double time when he complies, “[Y/N], [Y/N], [Y/N].” He regains his words again, “I, k-kinda get why you got so… antsy earlier.”

“Oh, really?” you say, forgetting how desperate you are, “is that what’s happening to you? You’re getting antsy?”

“Yes!” he yells as you rub yourself against him, “I get it I get it I get it I get it I get it! Just do something already!” He mumbles something about how someone as magnificent as him shouldn’t have to beg.

“You better get used to it,” you pant, “cause we’re certainly gonna do this again. And again, and a few more times after that.”

Sans yanks your head down to his, swearing his praises and his discomfort and his irritations into the confessional that is your mouth. You swear you can hear something about how you’re “better than any taco” among his list of praises and something like “my cape is kinda choking me right now” among his grievances.

The quiet dom that suddenly grabbed a hold of you fades away as the “heat” comes back with a vengeance. It whispers to you how needy he is right now, how desperate and wanting he is, and how it’s all for you. It goads you into stopping so you can line up the both of your privates. You steal a glance at Sans, your breath leaving you as his glowing blue eyes bore into yours. His eyes contain all the affection and the love in the world, his flushing face reminding you of your shared desperation. You decide that you’re ready to finally be one with the skeleton you love more than anything, so you bring your hips to his and… wait, shit, where do you put your…?

“[Y/N],” Sans moans, “please, I’ll do anything, I’ll even let you cook tonight. Even though it won’t be as good as mine.” He mumbles under his breath.

You grunt ferally, ignoring his last comment like the too-horny-to-care beast that you are, “where the hell do I put it.”

“What’d you _mean_ where do you put it?” Sans asks, clawing at his face in desperation.

“I mean!” you growl, “where! Do! I! Put! It—hold on it’s doing something.”

You both watch in rapt fascination as his tentacle genitals start undulating wildly. Neither of you are entirely sure what the thing is doing: he might blame its glowy properties (it’s so bright it’s difficult to get a read on what it’s doing), you’d blame his inexperience (you’d further supplement this by pointing out that he’s not even sure what it’s doing if you had known that). A searing pleasure that starts at your loins and rockets through the rest of you sends a howling moan out of your throat. Sans, either startled by your sound or the similar if not lessened feeling, shrieks in bliss and arches back into the bed. You arch over Sans, partially from the pleasure conforming your body to its whims, partially out of curiosity for what the hell just happened. You find his tentacles genitals/entrance (there’s really both down there) just entangled with yours.

You’re allowed little more than a few seconds of looking before your body tenses at the foreign yet not-so foreign feeling of overcharged magic trying to make its way into you. You can feel the seemingly sentient substance coaxing you forward and deeper into it. The retracting pleasure is all the encouragement you need to push forward into the mass of magic that is Sans’s genitals. Once your hips are close enough to feel Sans’s pelvic bones and the heat coming from his soul, the mass acts once again. The odd mass breaks into many different parts to begin an onslaught against the both of you.

A few longer parts of it break off from the rest to borrow their way inside you. Despite how overwhelming they are, the gently slide their way inside you. If you had your full senses, you might have noticed that they were producing some kind of slime to make the entrance easier, even if you really didn’t need it. Although, at the moment, neither of you can even think about thrusting, the appendages still manage to fuck you. A few of them (there are so many in you right now you can’t even fathom it), twist into your walls, guided not by any knowledge of what to do but instead a sort of instinct to how to make you squirm. Despite their lack of planning, some of them manage to bury into particularly pleasant spots. A few more are pumping in and out of you with reckless abandon, none bothering to copy the others’ pace.

A few of the shorter ones focus more on the parts of you on the outside. These ones, though shorter than their brethren, still manage to work the sensitive flesh around your hips. Some even stubbier ones are prodding at your exposed bits, seeking the most sensitive parts. Pretty much all of you is a sensitive part right now, so they really don’t have to look far. The shortest ones wrap themselves around you, forming a sort of sleeve or a cover that your hips can’t help but rock into. You can’t tell if you’re inside him, or if you’re just uselessly grinding into his out of control genitals, but you can’t care. You simply try to enjoy the sensation as much as possible. The grinding/fucking is so sloppy that you slip out of him from time to time, only for the sentient mass to drag you right back in.

Your brain is too preoccupied to pay much attention to the skeleton you’re fucking, but from what you can make out he’s having a pretty good time. He twists and squirms against you, doing his best not to fall apart then and there. His face, despite having no blood whatsoever, is flushed a heavy aquamarine. From embarrassment or bliss, you really don’t know (though you would guess both). He squeals every time you accidently or purposefully knock into him, a sound of pained pleasure that you can readily admit that you share. There’s not a word that you can make out through his babbling or the intense pleasure.

The stuffy air fills with the smell of a bug zapper and the gentle hum of magic. You honestly wouldn’t know what that means if not for the sudden increase in Sans’s sounds and the thrashing of his body. It’s also plainly obvious by the sudden quaking of the many different tentacle genitals all over and inside your hips. You’re not far behind him (you think you came a few times during this, actually), evidenced by the uncontrollable shaking of your body and the mummers of praise and nonsense coming from your lips. You smack those lips onto his as your body releases its labors for the last time (tonight) inside and outside of your tiny skeletal lover. He follows soon after, your hips and insides getting pumped full of his “creation juice”.

With his hefty helping of cum, you find your body, at long last, cooling down. You flop like a boneless ragdoll onto a pile of bones similarly gel-like. You pant breathlessly onto his porcelain white face, muscles too unresponsive to do anything resembling movement for a while. You feel the last of his magic pulling away from you, disappearing back into his soul or wherever the stuff happens to go. You feel his pudgy hands nudging you off him, mumbling something about (somehow) needing to breathe. You (somehow) find the strength to roll to the other side of the thoroughly ruined bed, the springs crying out from your abuse.

“I love you,” you croak unsexily into his tired face.

“I love you too,” he breathes back, doing his best to snuggle into you.

“Sorry about the sheets,” you say, covering the both of you with them, “and sorry about… this, I suppose.”

“No need,” he whispers as his consciousness leaves him for the night, “this was the best taking-care-of-the-sick-day ever.”

You giggle, “good night, Bluebs.”

He answers you with a cartoonish snore, having faded away to dream land before he could return the kind words. You smooch him on the head, and follow him there.

…

You step out of the bedroom, hair more of a mess than it has been in a while and clothes about as nasty as they can get. If you aren’t the pinnacle of why passing out after sex isn’t quite as good as it sounds, then you must simply be a gross son of a bitch. Sans was still asleep when you woke up, odd for the active guy but after a night like that you can’t say you blame him: it was his first time, and you did kind of go super crazy on him. It feels wonderful knowing that finally, even if it was in a way you wouldn’t have even considered if you weren’t horny as hell, you managed to get together with the guy you loved. That, and you’re finally out of your hot and heavy period so you’re bound to feel better. Besides needing a shower and food, you can’t say that you’ve felt this good in a long while.

“Good morning, [Y/N],” Papyrus greets coldly from the couch, “how’d you sleep?” The TV is on, playing something with Napstabot no doubt, but all his attention is completely on you.

 _Well, I’m not feeling quite so cheery now_. “Fine,” you whimper, trying to find a way to get into the bathroom without looking like you’re trying to escape this conversation (which you totally are), “how… how did you sleep?”

“Just fine,” he says, not taking his eyes off you for a moment, “I crashed at Asgore’s, old goat’s always happy to have a guest.”

You laugh nervously, “yeah, he is an excellent host.” You clear your throat, doing your best to hide the blue “creation juice” (you hope you don’t keep calling it that) leaking down your undies, “how come you uh… how come you slept at Asgore’s?” _Fuck why did you ask him that you’re not ready for this conversation FUCK you want to fucking live. You’ve seen what this guy can do. He’s threatened to do worse to you too. This is just like those fathers that swear they’re going to shoot their daughter’s boyfriends if they bring her home late. And you just slept with his brother. Oh God you’re so dead_.

Papyrus chuckles, the usually merry sound sending chills down your spine, “I think you know.”

You weigh your options on what you can say to possibly defuse the situation. You could barricade yourself in Sans’s room, as you doubt he would try anything if his brother was around. You could play it off like you have no idea what’s going on. You could even tell him you were having a slumber party or something. Of course, you do kinda want Papyrus to like you and running away wouldn’t do that, you obviously know what’s happening, and you think lying would just make him angrier. You swallow hard, knowing full well that there’s no escape now. “I… was in ‘heat’,” you say at last, “and I didn’t remember it was going to happen and I tried to leave but he insisted I stayed and I didn’t think I could get home so I said yes and one thing led to another and he offered to help and I—we just kinda… please, please don’t hurt me.”

Papyrus grunts and begins to light a M-cigarette (a special kind that monsters make, much less dangerous than the human variety), “considered waiting ‘till you got here so I could kill you. I got so mad over the idea that you would jump my bro, cause of some stupid ‘heat’ thing.” One of his eyes light up as he looks at you, “still considering it, actually.”

Your legs quake from the wave of terror that Papyrus sends over you, “why… why didn’t you?”

There’s no pity in his steely gaze on your cowering form, only the reassured contempt of a man who knows he could smite you right then and there. Papyrus takes a long drag of his M-cigarette and languidly puffs it out. His voice is cold yet calm, “figured it would happen eventually, just didn’t expect you both to break so soon.”

“I’m so sorry I’ll do anything to make it up—you were expecting this?!” you brace yourself on the railing, you both flabbergasted and yet more relieved than you had been in a while.

He takes another long drag whilst nodding, “I knew he was crazy for you, and you weren’t exactly subtle either.” His eyes turn back to you, but you swear he’s looking lower than he should be, “and with that heat you go through, I figured it was a matter of time before you two were having some sort of R-rated fairytale going on.”

“You knew about the heat, too?” you whimper, realizing that maybe Papyrus really _was_ a royal scientist at some point. Or had some sense to him. Or could do minimal research.

“That’s why I was at Muffet’s when you came over,” he sits back onto the couch, reminiscing, “I didn’t know if you were aware it was going to happen, but I didn’t want to be around either way. I tried to convince Sans to spend the day with me or to cancel his little get together.” He runs a hand over his face, looking a little more tired than usual, “I let it slip that you were probably going to…” he gestures towards you in all your morning-after glory, “be ‘sick’, but he actually got excited about it. Said he would help you through anything.” He sighs, “I knew there was no use arguing with him, so I just let him do it. I thought to myself ‘well, he is the older brother here, and if he wants to scream like a xeno-morph with his friend, then so be it’.”

Tears of joy and relief flood your vision, “he knew? And he wanted to help?” Guess you know how he figured it out then. As you wipe the happy tears from your eyes, something hits you about what he said, “what do you mean ‘scream like a xeno-morph’?”

Papyrus leans back so far on the couch he isn’t even looking at you anymore, “I thought the worst of it would be over in like a few hours, so I came home early.”

“Oh,” you say, suddenly knowing what Papyrus was talking about.

“I came in the door, ready to heat up some leftovers for you love birds or something.”

“Oh, please no,” you pray, a particular moment reentering your mind.

“And what do I happen to hear,” he half chuckles, “coming from by bro’s room but you two screaming your lungs out like it was something to do.”

You recall the part of the evening in which Sans’s junk wrapped itself around yours like a vice. You thought you were both being a little loud. “I’m so sorry,” you say slowly, “I am so freaking sorry.”

Papyrus waves you off, “s’no problem.”

You take a moment to catch your breath after that hair-raising ordeal, “oh thank God.

He takes one last drag of his cigarette, amusement returning to his boney face, “I wanted to tell you that I’m not on the menu.”

Despite the confusion, you rush to say, “Papyrus, I don’t know what you think of me, but I swear that I really do love Sans.”

“Sorry pal, didn’t mean to worry you,” he gestures down to your leg, where a viscus blue liquid was making its way down, “you were just drooling over there, that’s all.”


End file.
